On the ultra smoked and salted herring, a version of red herring, produced more for its preservation qualities than for taste or nutrition
Black Herring is essentially red herring smoked for three months rather than a few weeks. If red herrings will last a year in more-or-less any climate, black herrings will survive until the End of Days. Possibly longer. It may not be produced anymore – I’ve not come across it – but it used to be exported to the Caribbean and Africa.
Jane Grigson, in Fish Cookery (1973), writes, When I heard that Zimbabwean farmers buy them to supplement the porridgey diet of their black workers, I felt that herrings were still too close reminders of slavery to be comfortable.
Black herring is not mentioned much in the historical sources, if at all. It may originally have been thought of as a grade of red herring – which came in a variety of strengths and shades.